Dietary intakes of flavonoids and carotenoids and the risk of developing an unhealthy metabolic phenotype

Dietary polyphenols and the risk of metabolic syndrome: a systematic review and meta-analysis

BACKGROUND

Accumulating evidence has suggested that dietary polyphenols may be protective against metabolic syndrome (MetS); however, the available evidence is contradictory. The aim of this meta-analysis was to assess the association between dietary intake of polyphenols and the odds of MetS.

METHODS

The PubMed and Scopus databases were systematically searched to obtain eligible studies. The risk of MetS for the highest versus the lowest intakes of total, subclasses and individual polyphenols were examined by pooling odds ratios (OR) and 95% confidence intervals (95%CI) using the random effects model.

RESULTS

A total of 14 studies (6 cohort and 8 cross-sectional studies) involving a total of 50,366 participants with 10,879 cases of MetS were included. When various polyphenol compounds were pooled, they were significantly related to a 22% decreased odds of MetS (([5 studies]; OR: 0.78; 95%CI: 0.72-0.85). Higher intakes of total flavonoids (([9 studies]; OR: 0.78; 95%CI: 0.72-0.85), flavan-3-ols (([2 studies]; OR: 0.64; 95%CI: 0.43-0.94), isoflavones (([3 studies]; OR: 0.84; 95%CI: 0.75-0.93), stilbenes (([4 studies]; OR: 0.86; 95%CI: 0.76-0.97), flavones (([2 studies]; OR: 0.79; 95%CI: 0.71-0.89), and quercetin (([2 studies]; OR: 0.63; 95%CI: 0.43-0.93) were also significantly associated with a decreased risk of MetS. The associations were not modified by the age of the participants. No association was found for total polyphenols, phenolic acids, lignans, anthocyanins, and flavonols.

CONCLUSION

The results of this meta-analysis supported that higher polyphenol intake can lower the risk of MetS.

Association of dietary flavonoid intakes with prevalence of chronic respiratory diseases in adults

BACKGROUND AND AIMS

Flavonoids are a class of secondary plant metabolites that have been shown to have multiple health benefits, including antioxidant and anti-inflammatory. This study was to explore the association between dietary flavonoid consumption and the prevalence of chronic respiratory diseases (CRDs) in adults.

METHODS AND RESULTS

The six main types of flavonoids, including isoflavones, anthocyanidins, flavan-3-ols, flavanones, flavones, and flavonols, were obtained from the National Health and Nutrition Examination Survey (NHANES) 2007-2010 and 2017-2018 by the two 24-h recall interviews. The prevalence of CRDs, including asthma, emphysema, and chronic bronchitis, was determined through a self-administered questionnaire. The analysis included 15,753 participants aged 18 years or older who had completed a diet history interview. After adjustment for potential confounders, the inverse link was found with total flavonoids, anthocyanidins, flavanones, and flavones, with an OR (95%CI) of 0.86 (0.75-0.98), 0.84 (0.72-0.97), 0.80(0.69-0.92), and 0.85(0.73-0.98) for the highest group compared to the lowest group. WQS regression revealed that the mixture of flavonoids was negatively linked with the prevalence of CRDs (OR = 0.88 [0.82-0.95], P < 0.01), and the largest effect was mainly from flavanones (weight = 0.41). In addition, we found that flavonoid intake was negatively linked with inflammatory markers, and systemic inflammation significantly mediated the associations of flavonoids with CRDs, with a mediation rate of 12.64% for CRP (P < 0.01).

CONCLUSION

Higher flavonoid intake was related with a lower prevalence of CRDs in adults, and this relationship may be mediated through systemic inflammation.

Dietary inflammatory potential and biological aging among US adults: a population-based study

OBJECTIVES

The rate of biological aging is influenced by various factors such as genetics, environment, and diet. The dietary inflammatory index (DII) is strongly associated with various chronic diseases. The aim of this study was to investigate the association between DII and biological aging in US adults using quantitative indicators.

METHODS

Based on data from the National Health and Nutrition Examination Survey (NHANES) 1999-2018, weighted multiple linear regression models, generalized weighted models, and smoothed fitted curves were used to investigate the linear and nonlinear relationships of DII with four biological markers of aging (biological age, phenotypic age, telomere length, and serum klotho concentration).

RESULTS

A total of 35,575 adult participants with complete data were included in the study. After adjusting for all confounders, significant positive correlations were found between DII with biological age [0.070 (0.045, 0.095)] and phenotypic age [0.421 (0.371, 0.471)], with an increase of 0.07 and 0.42 years in biological age and phenotypic age, respectively, for each increase in DII score. The negative correlations between DII with telomere length [ - 0.005 ( - 0.008, - 0.002)] and klotho [ - 3.874 ( - 7.409, - 0.338)] were significant only in partially adjusted models and differed across subgroups.

CONCLUSIONS

In the current study, higher DII scores (greater pro-inflammatory dietary potential) were associated with biological aging. These findings may contribute to the development of aging prevention strategies through dietary interventions.

Dietary determinants of healthy/unhealthy metabolic phenotype in individuals with normal weight or overweight/obesity: a systematic review

Objectives: Nutritional factors are amongst the major determinants in the onset and development of obesity and metabolic complications. Nevertheless, the dietary determinants of metabolic health are not completely elucidated. The aim of this systematic review is to investigate nutritional and dietary factors that may contribute to metabolic heterogeneity in individuals with obesity or normal weight. Methods: A literature search was performed in PubMed, Scopus, EMBASE, and google scholar databases until August 2021, to locate studies that examined metabolic health and its association with intakes of specific foods or food groups, nutrient intakes or status, as well as adherence to certain dietary patterns. Two researchers had independently screened titles and abstracts, examined full-text studies, conducted data extraction, and evaluated their quality using the Newcastle-Ottawa Scale. Results: Twenty-seven studies, with a total of 39518 subjects, were included. Of these studies, 11 articles evaluated the association between different dietary patterns and metabolic phenotypes, while 15 had investigated the association of single food/nutrients intakes or nutrient status with metabolic phenotype, and one paper evaluated the association of dietary inflammatory index with metabolic health. The findings of these studies propose that healthy dietary patterns such as the Mediterranean pattern, Dietary Approaches to Stop Hypertension, and population-derived patterns (such as the "Healthy" and "Fruit and vegetable" patterns) were associated with higher odds of the metabolically healthy phenotype. Higher intakes of fruits, vegetables, dairy products, coffee/tea, vitamin D, magnesium, and flavonoids, were suggested to lower the risk of developing metabolically unhealthy phenotype, while, higher consumption of saturated fat, carbohydrate and sugar-sweetened beverages, fast foods, organ meats, and a pro-inflammatory diet increased the risk. Conclusion: Results from published studies, which were mostly cross-sectional, suggest that higher adherence to unhealthier dietary patterns, characterized by the consumption of refined and processed foods, was associated with a lower likelihood of having a healthy metabolic phenotype, while the opposite was observed for healthier dietary patterns. Findings may be used in developing nutritional strategies aimed at improving metabolic health in the population.

Obesity considerations during the COVID-19 outbreak

The worldwide population is facing a double burden of epidemic, the COVID-19 and obesity. This is even more alarming as obesity increases the COVID-19 severity. However, the relationship between obesity and COVID-19 severity is more complex than a simple association with BMI. In particular, obesity has been associated with low death rates in patients with acute respiratory distress syndrome, a fatal comorbidity to COVID-19, possibly due to the obesity paradox. Also, visceral adiposity could be a major risk factor for COVID-19 severity, due to its immune activation component, release of angiotensin-converting enzyme 2 and involvement in the cytokine storm, hypercoagulability and embolism. A poor antioxidant nutritional status also weakens the immune system, increasing inflammation and infection risk. Moreover, the COVID-19 lockdown might impact lifestyle patterns, mental health and weight bias, worsening the obesity then COIVD-19 situation. On the other hand, health care expenses and productivity loss are expected to increase during the concomitant epidemics. The co-occurrence of obesity and COVID-19 is a major challenge at both public health and economic levels that should urgently be taken into consideration. The identification of COVID-19 weight related risk factors and the development of appropriate weight management programs are needed to tackle the concomitant epidemics.